FIGHTING THE CHANNELED APPLE SNAIL

For years, biologists thought they had identified the channeled apple snail as the ravenous monster attacking lakes across Florida.

Now a South Florida researcher says they have discovered a nearly identical twin that is bigger and badder.

"They are both bad news, but one is worse," said Timothy Collins, an associate professor of biology at Florida International University in Miami.

The finding comes as the destructive snails have started showing up in Lake Apopka, posing a new threat to one of Florida's most-polluted bodies of water -- one that has already undergone millions of dollars in restoration efforts.

"It could take years to eradicate, or it may not be possible," said Jim Peterson, a St. Johns River Water Management District field supervisor for Lake Apopka who heads out twice a week to find and destroy the exotic snail eggs. "But we can try to limit how they spread."

Plotting the battle could change now that researchers, using techniques similar to those of police crime labs, try to learn more about the threat from the invasive snails and how they spread, devouring most aquatic plants in their path.

Next month, a newly formed joint task force will meet in Tallahassee to allow top experts to discuss the new information and how it may affect their coming war against the enemy.

"A few weeks ago we thought we could identify them -- now we're not sure," said Sherman Wilhelm, director of the state Division of Aquaculture. "It's very confusing."

The channeled apple snails are different from their smaller relatives, Florida's native apple snails. The native snails are considered an important part of the state's waterways. They provide food for birds and animals, while their numbers are controlled by predators.

If the golf-ball-sized apple snail is the good guy, the baseball-sized channeled apple snail is the villain. The huge snails reproduce quickly and can destroy aquatic plants at an alarming pace. But in addition to the common channeled apple snail, Collins has discovered a separate variety, the island channeled apple snail, in several Florida water bodies.

Though the adult island snail is a bit bigger, its eggs are smaller, allowing it to reproduce faster.

Both are awful news.

"It's a little like the difference between knowing you have a slow-growing cancer and a fast-growing one," he said.

Word of the new adversary has unnerved state officials, who have watched the spread of the channeled apple snails in horror.

Biologists thought the common channeled apple snail had spread like crazy throughout Florida in the past decade -- sometimes removing virtually all signs of other life from infested lakes. However, the new research shows the more exotic island snail should take most of the credit.

The channeled apple snails have long confounded experts.

The first channeled apple snails were discovered in Florida in West Palm Beach in the late 1970s, but that was a subspecies that never spread beyond the area.

The channeled apple snails have few, if any, predators. They're also tolerant to changing environmental conditions and are difficult to control with chemical pesticides.

Channeled apple snails have affected several Central Florida lakes, including Lake Brantley in Seminole County, Lake Tohopekaliga in Osceola County, Shingle Creek in Orange County and Lake Linda in Lake County. They've been found in most parts of Central and South Florida, and are turning up around Jacksonville and Tallahassee.

Attention to the island snails started recently when Collins presented information to the National Park Service about slimy critters taking hold in the Everglades. Collins linked that species to water bodies across the state.

Collins has been conducting two years of federally funded research with snail experts Robert Cowie and Ken Hayes at the University of Hawaii. They took samples of channeled apple snails in South America as well as those found in Florida's natural-history museum collections and different water bodies in the Sunshine State.

The group used tissue samples, analyzing their genetic makeup through DNA to identify them. That showed that Florida, for a large part, is dealing with the island snail.

"Once we have the genetic data in hand, it is easier to discriminate these things," Collins said. "What we called channeled apple snails are really three distinct things, and we have been treating them as one."

Knowing more about their enemy could help the state study them. "This might have implications to trying to stop the spread of these things," Collins said.

Collins and others say that even though the different types of exotic snails all have certain effects on the environment, knowing exactly which ones they are dealing with can help to understand what they eat, how much they eat and how quickly they can reproduce.

Wilhelm said Collins, as well as other biologists and state agencies, are all doing their own studies of the problem. He hopes that next month's task-force meeting will be the first of many where they jointly work toward finding a solution.

"They all have pieces to this puzzle. This will bring all the people together and put those pieces together," Wilhelm said.